During the course of constructing a building out of drywall, openings through the drywall intended to accommodate electrical receptacles and the like are sometimes incorrectly positioned. When this occurs the unwanted opening through the drywall must be patched. There are, of course, an infinite variety ways that a person can find himself or herself with an unwanted hole or opening through the drywall that must be patched.
Although a number of patents disclose methods or apparatus for patching drywall, none of the solutions disclosed has achieved commercial acceptance. U.S. Pat. No. 3,999,347 which issued to Devlin in 1976 entitled "Handy Helper", discloses a clamp like tool. This tool has a bow member and a centrally positioned adjustable stem member. The stem member is attached to a piece of scrap board. The scrap board is inserted through an opening in the drywall that is to be patched. The scrap board is held up against the inside of the drywall by tightening the stem of the tool. A patching compound is then applied to the opening, using the scrap board for rear support. When the patching is completed, the stem is withdrawn and the scrap board is left in the wall. The scrap board serves as temporary backing while during the patching process. U.S. Pat. No. 4,358,495 which issued to Parker in 1982 is entitled "Drywall Patch Kit". The kit includes sandpaper, a putty knife, a tube of joint filler compound, and a plurality of patches of varying sizes. Each patch consists of two circular-shaped layers of drywall paper cemented together. The patch is made pliable by dipping in water prior to application. The patch is slightly larger than the opening being patched. This provides a single thickness of material around the outer edge of the opening for blending in with the wall and a double thickness over the opening for enhanced reinforcement. U.S. Pat. No. 4,620,407 which issued to Schmid in 1986 is entitled "Method for Drywall Patching". The method disclosed involves the use of a rectangular shaped repair plug having a front wall, a rear wall and edges which slope inwardly from the front wall to the rear wall. A rectangular shaped opening is made through the drywall with corresponding sloped walls. The mating of the sloped walls of the repair plug and sloped walls of the opening serve as backing for the repair plug.
Each of the patents described above provides certain advantages and has certain inherent disadvantages. With the drywall patch disclosed by Parker, care must be taken to ensure that the patch does not slide laterally out of position during application. Once the patch has dried and set into position, problems can be experienced due to the fact the patch has no permanent backing. An object striking the patched area would likely punch a hole through the two thin ply patch material. The teaching of Devlin requires the use of a joint filler compound without backing. As with the Parker patch, the Devlin patch would be susceptible to damage is accidentally struck. A further problem may be experienced even in the absence of striking if the joint filler compound experiences shrinkage. The most practical of the teachings is that of Schmid. The patch taught by Schmid is installed in such a manner that it has solid backing. It takes preparation in order to ensure that both the opening and the patch have sloped edges. It is difficult, if not impossible, to get the sloped edges exactly perfect, so that the distance that the patch extends into the opening will vary. When the patch extends into the opening deeper than is desirable, filling will be required. The patch should be durable enough to withstand blows experienced through normal use.